Good decision ?!
Well, for the Obama supporters it is, but on the other hand he'll get attacked because of the jobs that are - well, delayed.
In general I'm not opposed to pipelines (there's a huge one running through my county called
TAL "Trans-Alpine-Pipeline" from the port city of Triest in Italy I think to some city in Munich where the oil gets into a refinery or whatever it is called, and there's been no spill so far in about 50 years and it's running through the National Park Hohe Tauern)
So, if they can find another route that poses absolutely no danger to the water ressources and they make sure that there will be no spills, I'd favor the project.